1. Technical Field
This invention relates in general to communications and more particularly to an efficient transceiver design for mobile phones.
2. Description of the Related Art
Mobile phone communications are now common throughout the world However, there are several communication standards over which mobile phones communicate, using different frequency bands. For example in Europe two cellular standards are available, GSM 900 (Global System for Mobile) using the frequency range of 925-960 MHz, and DCS 1800 (Digital Cellular System) using the frequency from 1805 to 1880 MHz
For manufacturers of mobile communications equipment, it is desirable to use a single transceiver to cover multiple frequency bands to provide equipment that can be used with either standard when a multi band cellular phone is required to cover a wide range of operating frequencies in two or more separate frequency bands, however, it has been necessary to use several oscillators and synthesizers at RF and IF frequencies. The resulting transceiver is large, complex and uses a significant amount of power. Since battery life is a primary consideration in a cellular phone purchase, it is extremely desirable to reduce the amount of power consumed by the cellular transceiver circuitry.
Accordingly, there is a need for a mobile phone transceiver with reduced circuitry requirements.